Liquid crystal displays (“LCD”) are used in a variety of electronic devices such as cellular phones, wireless devices, PDAs, and the like. LCDs are formed by stacking layers or portions of layers of materials including glass, plastic, metals, and organic films. LCDs provide both a reflective layer and a clear layer which in combination with other layers permit an image to be seen on one side of the display stack. In many hinged devices such as clamshell cellular phones, two LCDs are provided on the device. For example, many cellular phones have a main display and a caller ID (“CID”) display.
LCD displays are commonly backlit using internal lights, such as from LEDs, EL panels, or lamps. Lights and/or LEDs may be located in the electronic device away from the back area of the LCDs. A light guide or light pipe can be used to couple light from the LED or lamp light source to the back of the LCDs to illuminate the LCDs.
Multi-display electronic devices may provide that the LCDs share the same light guide. This is done to reduce overall size, parts count, and cost. One problem with two or more LCDs in an electronic device sharing the same light guide is that the light is distributed among the LCD even when they do not require backlighting. Light guides shared by two LCDs are known as two-way light guides. Two-way light guides are optimized for light to travel in one preferential direction instead of two directions. For example, two-way light guides are optimized for the light to travel in the direction of the main display with a significantly lower amount of light reaching the CID display. These “leaky” light guides take light from the main display to illuminate the CID display, thereby providing sub-optimal lighting for the CID display.
Therefore a need exists to overcome the problems with the prior art as discussed above.